Windmill on the Wye

Windmill on the Wye

The picture above is an oil painting attributed to Edward Niemann and inscribed on the reverse "On the Wye".
I'm trying to find out more about the mill pictured, and wonder if anyone can help.

This is not a location I recognise - and to be honest it's more than possible a lot of artistic licence
may have been applied here. First of all I'd say it is most unusual to have a (corn) windmill located
right by a river - after all water power is generally far more predictable than wind, so when you had a
choice, you would build a watermill in such a location. The mill shown is a post mill, where the whole
structure is turned to face the wind, and I know of no such example in Britain where the access to the
mill was on the side (if you think of the sails as being on the front) - all such access was to the rear,
where the weight of the steps were used to help counterbalance the weight of the sails on the front.

My conclusion is that the scene may have been painted "from memory", rather than being a particular image
of an actual place - but can anyone help confirm or deny that?